Method of producing oxidation products from gaseous hydrocarbons



J. H. JAMES METHOD oF PRODUCING OXIDATION PRODUCTS FROM GAsEoUs HYDROGARBONS June 26, 1928.

wrm Esse Patented `June 26, 1928.

UNITED STATESv 4'1,675,029 'PATENT oFFlcE.

JOSEPH HIDY JAMES,- OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR, BY `DIRflilC'IL AND MESNE ASSIGNMENTS, T0 CLARENCE P. BYRNES, 0F PITTSBURGH, PENNSYLVANIA,

TRUSTEE.

METHOD 0F PRODUGING OXIDATION PRODUCTS FROM. GASEOUS HYDROCARBONS.

Application med November 21, 191s, serial No. 132,570. 'Renewed Maren 2s, 1925.

F igure 1 is a side elevation, partly in section, showing one form of apparatus for carrying out my invention.

Figure 2 is an enlarged section through the catalytic vessel, and Figure 3 is a sectional side elevation of one of the absorbers.

My invention relates to the manufacture of oxidation products from gaseous hydrocarbons and is'designed to provide useful 'products by a lpartial oxidation thereof which is-so controlled as not to reach a complete combustion stage.

As is well known, when llhydrocarbons which are gaseous at ordinary temperatures and pressures, such as methane, ethane, propane and butane which are present in natural gas, are mixed with air-in certain proportions and ignited, a nearly complete or a complete combustion takes place, the main products being carbon dioxide, carbon monoxide, steam, soot, etc., the proportion of these products depending upon the temperature, the proportion of air supplied etc.

As the result of a long seriesof experiments, I have discovered that if air or oxygen in some form be mixed with gaseous hydrocarbons in such proportions as to give a non-explosive mixture, and the mixture brought in contact with certain kinds of catalytic material, under pro-per temperature and gas velocity conditions, the reactions can be so controlled as to carry the oxidation of the hydrocarbon to a point short of complete combustion, thusv giving intermediate products such as aldehydes and acids.

The catalyzer causes the oxygen under these conditions to attack the hydrocarbons, carrying the oxidation to an intermediate stage, such as the aldehyde stage. It will be understood that if the percentage of oxygen or air is outside of the proper range for this process, the .oxidation will be carried to the point of self-sustained combustion which should be avoided; and by 'keeping the percentage of air within the proper vent self-sustained combustion occurring.

The catalyzers that ossess this remarkable roperty, and which -I have thus far 4-tested are the oxides of molybdenum, va-

' nadium, manganese, tungsten and uranium,

together with mixtures of these oxides with each other, or mixtures of these `oxides with other metallic oxides; land compounds of these oxides, such, for example, as molybdenum vanadate, cobalt molybdate, manganese molybdate, etc.

My investigations have led mey to believe that this remarkable property is possessed by the oxides and compounds of high meltingpoint, electronegative, low atomic vol-4 ume metals, such as given in the Lothar, Meyer atomic volume diagram, shown, for example, on page 62 of volume 2 of the 1907 edition of Roscoe & Schor'lemmers Treatise on Chemistry. In this diagram, the metals whose oxides and compounds which I wish to include in my broader claims are. on the descending side of the peaks beginning with the third peak of said diagram and including such metals as titanium, vanadium, chromium, manganese, zirconium, niobium or columbium and molybdenum. In other treatises than the one above referred to, the diagram has been further developed so that the vextension of the diagram includes thorium,

tungsten, and uranium-l inthe sa e classification. See Gavin & Lander ryistematic Inorganic Chemistry, -1907 edition, page 32 diagram. If I employ more than one of these oxides, y.I preferably mix the oxides of such metals with each other, or the compounds of each other, though as above stated, I may mix them with'other metallic oxides. I have tested the molybdates of manganese" and cobalt and also molyb-' denyl molybdate, and find that they possess this peculiar property which is probably possessed by other compounds of yhigh fmelting'point, electronegative, low atomic 'Ihev oxides or compounds -of these metals arel non-volatile at the temvolume metals.

peratures which I employ, and in my process, the temperature is kept below the volatilizing point of suchl oxi es or compounds.

With aVcat-alyst consisting of the oxides -of molybdenum produced by partial .reduction of molybdenum troxide, and using methane -as the hydrocarbon, the desired re range hereinafter referred to. I can pre-v action is very faint at 300 C.; is noticeable at 400 C.; measurable at 500 C.; with mod- 700 C. can be used.

I havefurther found-'that although-the aldehydic oxidation of methane can be ob:

tained at 450 C. to 500 C. with little or no carbon dioxide formation, the percentage of conversion in one passage through the catalytic mass is very low, amounting only to a few tenths of: one per cent. The best yields so far obtained, were with gas and air mixtures (having more than 16% methane, in order, in this experiment, to keep outside the 'explosive range which vis from 4% to %)V at temperatures from`530 to 700 C.

In the latter case the percentage of conver-x' sion is highern but is always accompanied V by a carbon dioxide formation. The percentage of methane passing into carbon dioxide can, however, be lowered, and the percentage passing'- into formaldehyde increased to as much as one-twentieth ofthe total, by increasing the velocity of the gas mixture 'through the catalytic mass.y These facts appear to show that the oxidation, in the presence of the catalyzers atleast` is progressive, tle formaldehyde stage definitely preceding the acid and the carbon dioxide stage. I will now describe one form of my apparatus and the method used therewith.

In the drawin s, 2 represents a reservoir of mixed air `an gas under slight pressure, from which the mixture passes. through a valved ipe3 to a' gas -meter 4. From the' meter t e mixture passes 4through a choke device 6, to preyent back firing, into pipe 7 and thence into the inlet passage 8 of t e catalytic vessel 9. This inlet passage is preferably arranged as shown, so that the cated before entering the l mixture will be c'atalyticchamberr The vessel is heated by any suitable means as, for example, a burner, or burners 10, the temperature ing carefully regulated to give the desired `partial oxidation'result. For this purpose, I showa pyrometer couple 11 in the catalytg ic vessel, extending through its wall and mediate stage s orto complete v type having a tap-0E, such as shown. In

isf-'ap aratus as shown, coolingwater enters't e right hand vessel through pipe 18, `passes upwardly around the, coil pi e thereinand thence through pipe19-tot e lower en'dof the other coollng vessel, and` lafter rising around the cooling pipe therein p out through outlet pipe 20. The

combustion,

valve tap-0E is indicated at 21. From this condensing apparatus, the uncondensed remainder passes through the pipe 15 and into A'a series of absorption vessels 1'6. These vessels are prefere. ly arranged in the gen# eral manner shown lin vFigure 3, the gas entering each one below the surface of the f liquidA and the surplus passing over to the next absorption vessel. I lhave shown each o f these absorption wells as surrounded by a water jacket 17'.

By such an apparatus, operated as above described, the partial oxidation productsl may be obtained, but in order to o erate this commercially, it will be desirab e for the reasons above given, to pass the mixture o f gaseous hydrocarbon and air through a series of these units, each made up of a catalyzing apparatus and the necessaryabsorption, or condensing and absorption vessels, in'order to obtain the desired yield of the intermediate` products such as alde hydes. `The remainder will pass into carbon dioxide and flow out unchanged with the exit gas.

Where the gaseous hydrocarbon is methane, the reactions are as follows: A

1. Formaldehyde formation;

CH4+O2=CH2O+H2O Methane oxygen` formaldehyde water. 2. Carbon dioxide formation cH,+2o= co2 21120 Methane oxygen-carbon dioxide wut er.

The treatment of thel products .issuing from the. catalytic apparatus depends on the particular gaseous hydrocarbon treated.

With methane, the formaldehyde and steam produced, togpther with allthe other constituents 4of t e gas stream, are coo ed, con'- dens'ing the steam. In this way part f the formaldehyde is obtained in the water of condensation by absorption and the y additional absorption vvessels containing water serve to recover the greater .part of the formaldeh de which remains in 'the gas stream. in water may be concentrated by various means well known to industrial chemists,` in order to obtain a solution of commercial stren th. l.

Ot er methods of recovering .formaldehyde may be used as, for example, by pass# ing the exit gas mixture into absorbers-containing a saturated solution of sodium acid sulphite, and later decomposing the .formaldehyde-sulphite compound by well known ese solutions of :formaldehyde chemical means and recovering a water so lu-` tion of formaldehyde." With heavier gaseous hydrocarbons, the aldehydes can be' recovered in most cases ,by condensation, and -in all c asesy condensation followedby absorption. y

process may be used with any hydrocarbons or hydrocarbon derivatives or compounds which January 22, 1919.

-are in gaseous form when the air or oxy-v gen-containing gas ismixed therewith. l'

` T he advantagesof my invention will be obvious to industrial chemists, since a number of valuable industrial products can be" `obtained by this simple and effective method.

,one-tenth of the total methane oxidized, was

obtained. L

The claims in this application are limited tothe oxidation of hydrocarbonsiwhich are gaseous' at normal temperatures and pressure. The broader claims. to. partial oxidation of hydrocarbons appear in my co-pending application Serial No. 272,567 tiled Many changes ma -be made in the apparatus' employed, t e particular catalytic mass used etc., without departing from my invention. l

I claim:

^ 1.-:[11 the method-of maling partialoxidation products, the steps consisting of passing a mixture stream containing oxygen and hydrocarbon which is gaseous at normal temperatures and pressures over a catalyst,

-andjmaintaining the reaction temperature below that of continuously self-sustained combustion and within the partial combustion range .below the volatilizing point of the catalyst. i v

2. In the'method ofmaking partial oxidation products from a hydrogen-carbon in the partial oxidation vrangefor thefmix-A tureused, and' passing in contact with saidcatalyst a mixture of oxygen-containing gas 'and a hydrocarbon which is gaseous at normal temperatures and pressures in pioportions outside the explosive range and at such -a speed relative to the catalyst that the time of sojourn of the mixture therein is relatively short. Y

5. In the 'manufacture of partial oxidation products, the steps consisting of maintaining a reaction zone at a temperature' be,- 'low about 550 C. and within the partial oxidation range for the mixture used, and

.passing through said zone a mixture of oxytion products, the steps consisting of maintaining a catalytic reaction zone at altemperature belowabout 550 C. and Within the partial oxidation range for the mixture used, and passing through said zone Vin contact with thecatalyst therein a mixture of oxygen-containing gas and a hydrocarbon which is gaseous atl nor-mal temperatures and pressures in proportions outside the explosive range, and extracting products' from the tail 7. In the manufacture -of partial oxidation products, the steps consisting of maintaining a reaction zone at atemperature begen-containing gas and a hydrocarbon' which is. gaseous at anormal temperaturesA and pressures in roportions outside the explosive range, and) extracting'produets from the tail gas.

6. In the manufacture of partial oxida'- low about 400 C. and within the partial oxidation range for the mixtureiised, and pass ing through said zone a mixture of oxygen,

containing gas and ahydrocarbon which is gaseous at normal temperatures and presl' stream' containing hydrocarbons which area' sures inV proportions outside the explosive .gaseous at normal-temperatures, -and 'presgas into contact with 'catalytic materia and maintaining the reaction zone temperature below the"volatilizing `temperature of the catalyst'.

vim'

mixture use 3. In, the manufacture of partial oxida-f' tion-products, the steps consisting of maintaining a `reaction zone at a temperature `below that ofgself-sustained combustion and within the artialoxidation-range -for the d) and passing through said zone a-mixture of oxygn-containing gas` and a temperatures and pressures in proportions outside the l'explosive range and at such a speed ielativeto the zone that the time ofsojourii 'of the mixture therein is relativelyV short.

fue

4. YIn the manufacture Aof partial oxidav.tion produets,the' steps consisting of -maintaining acatalyst at atempeiiaturedbelw that fof vseif-sustainei eombustiroiiaud. with# is'` gaseous at normal range, and extracting products from the tailY 8: In the manufacture of' partial oxidac partial oxidation range for' the `mixture used, and passing through said zone in contact 'with'the catalyst therein a mixture of 4oxygen-containing gas and a hydrocarbon which is gaseous at normal temperatures and pressures in proportions outside the explosive range, and extracting products from the tailga-s..

9. The method of making intermediate ox-- idation products from hydrocarbons which are gaseous at .normal ,temperatures and i' pressures, consisting in passing the gaseous stream -containing oxygen Vand containing' said gaseous hydrocarbons to a percentage greaterI than that within the explosive range I through a catalytic layer containing a com- V-pound of a high-melting-point low-atomic volume electronegative metal at a.- temperature below4 the volatilizing point of said metalcompound and at such temperature and velocity (higher with higher temperatures) that intermediate partial combustion products may be recovered. A

10. The method of making intermediate oxidation prodllcts from hydrocarbons which are gaseous at normal temperatures and pressures, consisting in passing a gascous stream containing said gaseous hydro v carbons and oxygen in relative percentages outside the explosive range in contact with a catalytic layer containing a compound of a high-melting-point low-atomic volume electrouegative metal at a temperature below the volatilizing point of said compound and at such a temperature and velocity (higher with higher temperatures) that intermediate partial oxidation products may be recovered.

11. `The method of making intermediate oxidation products from hydrocarbons gaseous at' normal temperatures. and pressures,

which are gaseous at normal temperatures and pressures, consisting inpassing a gaseous stream containing oxygen and said gaseous hydrocarbons through a relatively thin catalytic layer containing a compound of a high-melting-point. low-atomic volume electronegative' metal at a temperature below the volatilizing point of the compound and at such velocity and temperature that intermediate oxidation products may be recov- I ered, `recovering products therefrom 'by vforming chemical compounds thereof, and

repeating the operations on the residual gas mixture after said recovery.

13.7The method of making intermediate" oxidation `which are gaseous at normal temperatures products from hydrocarbons and pressures, consisting in passing a gaseous stream containing oxygen and said gaseous hydrocarbon in contact with a catalyst` containing a .compound of a high-meltingpoint, low-atomic volume electronegative metal, and maintaining the' temperature conuo I tial oxidation products aie ditions in the range where intermediate parf produced and below the volatilizing point o the said metallic compound.

14. In,` the method ofrmaking artial oxi-v dation products from hydrocar ns which are gaseous at normal temperatures and pressures, the`=steps consisting of mixing the preheated hydrocarbon gas withl an oxygencontaining gas and passing thel mixture in contact with a catalyst containing a compound of a high-melting-point low-atomic volume electronegative metal at a reacting temperature below the volatilizing point of said metal compound, and recovering the low that of self-sustained combustion andy within the partial oxidation range orthe mixture used, passing through said zone a mixture of oxygen-containing gas and a'hydrocarbon which is gaseous at normal temperatures and pressures in proportions outside the explosive range and at such a speed relative to the zone that the time'of sojourn of the mixture" therein is relatively short, and then passing the stream through a condensing coolerand then through a scrubber.

17. In the method of making partial oxidation products from hydrocarbons which are gaseousat. normal temperatures and pressures, the steps consisting of mixing the gas with an oxygen-containing gas in such proportions that the combustible gas per- V centage is greater than that within the explosive range, and passing the `mixture. in contact with a catalyst containing a comppund of a metal at a reacting temperture low the voltilization point`of the catalyst andat such velocity that part of the oxygen pressures, the steps consisting of mixing the gas with an oxygenfcontaimnggas in proportions outside the explosive range and passing the mixture in contact with a catalyst at lsuch velocity and temperature that part lof the oxygen remains uncombined and is present inthe aseous products.

19. In the met od of making partial oxi- I dation products from a hydrogen ;carbon stream containing hydrocarbons which are gaseous at normal temperatures and-pres-v sures, the Steps consisting' vof mixing the lao gas with an oxygen-containing gas in such ucts', and again vpassing the unrecovered proportions that the combustibleV gas perportions through a hot reaction zone, and 10 centa-ge is greater than that withinthe exmaintaining said zone at a temperature Withplosive range of the mixture, pasising the 4inJ the range to`produce intermediate oxida- 5 mixture through a hot reaction zone at such `tion products. v l

velocity and temperature that part ofthe In testimony whereof, I have-hereunto set oxy n remains uncombined and is present my hand. in t e product, recovering part of the prod- JOSEPH HIDYy JAMES. 

